This invention relates to miniature inductors and transformers. Transformers constructed in accordance with this invention have a number of applications in the electronics, telecommunications and computer fields.
The preferred embodiments of the present invention utilize a slotted ferrite core and windings in the form of flex circuits supporting a series of spaced conductors. A first portion of the primary and secondary windings of a transformer are formed as one flex circuit. The remainder of the primary and secondary windings are formed as a second flex circuit. Connection pads are formed on both flex circuits. One of the flex circuits is positioned within the opening or slot of ferrite core, the other flex circuit is positioned in proximity to the outside of the ferrite core so that the connection pads of both flex circuits are in juxtaposition. These juxtaposed pads of the two flex circuits are respectively bonded together to form continuous windings through the slot and around the core.
One significant feature of the invention is that the flexible nature of the flex circuit facilitates construction of a plurality of different transformer and inductor configurations. Thus, in one preferred embodiment, one of the flex circuits is folded along a plurality of fold lines to accommodate the physical configuration of the slotted core. In another embodiment, the flex circuit is passed through the slot in the ferrite core without folding.
Inductors and transformers constructed in accordance with the preferred embodiments of this invention offer improved heat removal, smaller size, superior performance, and excellent manufacturing repeatability. In addition, inductors and transformers constructed in accordance with the preferred embodiment of this invention are surface mountable without the need for expensive lead frame dies or pinning tools.